This invention relates to a low noise smoothing device for a power supply used for highly sophisticated electronic devices.
The need for a low noise smoothing device for a power supply incorporating electrolytic capacitors has been increasing as electronic devices become highly sophisticated. In particular, switching power supply which intermittently rectify a high frequency alternating electric current are widely used for electronic devices of office or home use due to their compact sizes and low prices. However, undesirable radiation referred to as Electro Magnetic Interference (E.M.I) emitted from the electrolytic capacitors incorporated in these power supplies due to a magnetic flux generated from internal electrodes of the electrolytic capacitors has not been prevented since any special attention has not been paid to an arrangement or connection of the internal electrodes. Therefore, a residual ripple noise and the E.M.I. from the power supplies are significant problems in the smoothing devices for the conventional power supplies incorporating the electrolytic capacitors which are developing into a public problem. The problem of the E.M.I. has not been resolved yet since those electronic devices still generate the ripple noise of 0.2% of an output DC voltage, that is about 100 mV-400 mV, despite efforts made by industries manufacturing the capacitors and the power supplies.